34 



ENTOMOLOGY 



The plumose antennae of the male mosquito (Fig. 44) are highly de- 

 veloped organs of hearing, and are used to locate the female ; they have 

 delicate fibrillae of various lengths, some of which are thrown into sym- 

 pathetic vibration by the note of the female (p. 94). 



Meloe has just been mentioned. In Sminthurus malmgrenii (Collem- 

 bola) the antennae of the male are provided with hooks and otherwise 

 adapted to grasp those of the female at copulation. 



Though systematists have recorded many instances of antennal 

 antigeny, the interpretation of these sexual differences has received very 

 little attention; a beginning in the subject has been made by Schenk, 

 whose results will be referred to in connection with the sense organs. 



FIG. 44. Antennae of mosquito, Culex pipiens. A, male; B, female. The antenna has a 

 short basal segment, not shown in the figure. 



Mouth Parts. On account of their greaf range of differentiation, 

 the mouth parts are of fundamental importance to the systematist, par- 

 ticularly for the separation of insects into orders. Most of the orders 

 fall into two groups according as the mouth parts are either biting 

 (mandibulate) or sucking (suctorial). Collembola and Hymenoptera, 

 however, combine both functions; Diptera, though suctorial, exhibit 

 various modifications for piercing, lapping or rasping; Thysanoptera 

 are partly mandibulate but chiefly suctorial; and adult Ephemerida 

 and Trichoptera have but rudimentary mouth parts. 



The mandibulate orders are Thysanura, Collembola (primarily), 

 Orthoptera, Dermaptera, Isoptera, Embioptera, Corrodentia, Mal- 

 lophaga, Plecoptera, Ephemerida (rudimentarily in adult), Odonata, 

 Coleoptera, Strepsiptera, Neuroptera and Mecoptera. 



